Loop antenna



C. A. RAABE LOOP ANTENNA Nov. 7, 1950 Filed Jan. 19, 1946 Patented Nov. 7, 1950 LOOP, ANTENNA Carl A. Raabe, Chicago, 111., assignor to American Phenolic Corporation, Chicago, 111., a corporation of Illinois Application January 19, 1946, Serial No. 642,258

2 Claims. (01; 250-3357) This invention relates to insulated wire and is more particularly concerned with the provision of an insulated wire adapted for use in the manufacture of loop antennas for home and portable radios.

Heretofore, it has been the practice in the manufacture of loop antenna wire to first braid a cotton jacket over the wire and then to impregnate the covered wire with a suitable plastic material. The present invention contemplates the provision of a loop antenna wire covered with a suitable dielectric material formed with means for interlocking engagement of adjacent loop convolutions when the insulated wire is spirally wound upon itself to form a loop antenna.

This invention further contemplates the provision of one form of insulated wire having an extrudable dielectric jacket provided with longitudinally extending ridges and grooves and flat parallel side walls, said ridges and grooves being formed for interlocking engagement when the insulated wire is wound upon itself to form a loop antenna. After winding the insulated wire into the form of a loop antenna, the several convolutions thereof may readily be secured together by means of a heat sealing operation. A bearing support is then molded around a portion of the loop antenna to support same.

This invention further contemplates the provision of another form of insulated wire in which the dielectric material is provided with tongues and grooves for interlocking engagement of adjacent convolutions when the wire is wound upon itself to form a loop antenna.

This invention also contemplates the provision of another form of insulated wire comprising a plurality of copper conductors enclosed by an extruded dielectric of substantially channelshape with side flanges for line engagement with the leg portions of an adjacent convolution when the wire is wound upon itself to form a loop antenna.

This invention embodies other novel features, details of construction and arrangement of parts which are hereinafter set forth in the specification and claims and illustrated in the accompanying drawing wherein:

Fig. 1 is a fragmentary front elevational view showing a loop antenna as formed from insulated wire embodying features of this invention.v

Fig. 2 is a perspective view illustrating the construction and manner in which one form of insulated wire is wound upon itself to form a loop antenna.

Fig. 3 is a perspective view showing a modified form of insulating wire in which the dielectric is formed with a tongue and groove for interlocking engagement of adjacent convolutions.

Fig. 4 is a perspective view illustrating another form of this invention in which a p urality of conductors are disposed within a channel-shaped dielectric, said'dielectric being provided with side flanges for line engagement with leg portions of an adjacent convolution when the insulated wire is spirally wound upon itself to form a loop antenna.

Referring now to the drawings for a better understanding of this invention and more partic' ularly to Figs. 1 and 2 therein, an insulated wire 6 is shown as comprising a copper conductor I which is covered by-a suitable dielectric material 8. In the manufacture of the insulated wire, the dielectric material 8 is extruded over the conductor I and formed with a longitudinally extending ridge 9 and a longitudinally extending groove Ill. The dielectric material may also be formed to provide fiat parallel side walls I l and I2 to facilitate the construction of loop antennas as hereinafter set forth.

In forming a loop antenna [3 of the type illustrated in Fig. 1, the insulated wire Bis spirally Wound upon itself by employing a suitable arbor, not shown, with the ridges 9 and recesses ID of adjacent convolutions in aligning engagement, as illustrated in Fig. 2. After the winding operation, the several convolutions of the wire 6 are adapted to be secured together by heat sealing same transversely of the loop along the side walls II and I2 and at spaced intervals about the circumference of the antenna, as indicated at I 4. During the heat sealing operation, the adjacent side edges of the convolutions are thus spot sealed together to provide a loop antenna construction in which the several convolutions of the insulated wire 6 will not readily be separated. However, it is contemplated that the several convolutions of wire formin the loop antenna may be secured together by means of strips coated with adhesive. In the final assembly of the loop antenna, it is contemplated that a bearing support I6 formed of suitable dielectric material, such as the type of dielectric material 8 employed in the wire 6, may be molded in position to enclose a portion of the loop antenna.

It will thus be seen that an insulated wire of the type illustrated in Fig. 2 may be spirally wound upon itself without difficulty to form a loop antenna having fiat sides suitable for bonded engagement by means of either a heat sealing operation or adhesive strips to prevent dislocation of the several convolutions, and that a bearing support may readilybe molded around a segment of the antenna thus formed to complete the assembly of the antenna.

Fig. 3 shows a modified form of insulated wire 6a comprising a copper conductor 1 having a dielectric material l8 extruded thereover. In this form of the invention, the dielectric material is formed with longitudinally extending tongues l9 and grooves 2i disposed on diametrically opposed sides of the dielectric for interlocking engagement of adjacent convolutions of the wire 611 when same is spirally wound upon itself to form a loop antenna.

Fig. 4 illustrates another modified form of insulated wire 61) comprising a plurality of conductors 22 enclosed in the base portion 23 of a substantially channel-shaped dielectric 24. A pair of flanges 26 extend outwardly in spaced parallel alignment from the base portion 23 to form therewith a recess 21 to receive the legs 28 of the dielectric when the insulating wire is spirally wound upon itself to form a loop antenna.

While this invention has been shown in several forms, it is obvious to those skilled in the art that it is not so limited but is susceptible of various changes and modifications without departing from the spirit and scope of the claimed invention.

I claim as my invention:

1. In a loop antenna, an electric conductor, insulation completely enclosing said conductor throughout its length to form an insulated cable, an elongated continuous projection formed upon one side of said insulation substantially coextensive with the length of the cable, the insulation on the opposite side of said conductor being provided with an elongated continuous indentation substantially coextensive with the length of said cable, said cable being arranged in substantially spiral form comprising a plurality of convolutions and with adjacent convolutions disposed in interlocked contact with each other, the projection of 4 one convolution in interengaging registry with the indentation of the adjacent convolution.

2. In a loop antenna, an electric conductor, insulation completely enclosing said conductor throughout its length to form an insulated cable,

an elongated continuous projection formed upon one side of said insulation substantially coextensive with the length of the cable, the insulation on the opposite side of said conductor being provided with an elongated continuous indentation substantially coextensive with the length of 1 said-cable, the cross-sectional shape of said insulation throughout the length of the cable being substantially uniform, said cable being arranged in substantially spiral form comprising a plurality of convolutions and with adjacent convolutions disposed in interlocked contact with each other, the projection of one convolution in interengaging registry with the indentation of the adjacent convolution.

CARL A. RAABE.

REFERENCES CITED.

The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 266,677 Corbett Oct. 31, 1882- 931,445 Low Aug. 17, 1909 1,739,246 Majce 1 Dec. 10, 1929 1,874,723 Dawson Aug. 30, 1932 2,002,344 Fischer May 21, 1935 2,081,634 McNamee May 25, 1937 2,204,782 Wermine June 18, 1940 2,218,830 Rose Oct. 22, 1940 2,282,759 Gavitt May 12, 1942 2,329,634 McDonald Sept. 14, 1943 2,403,093 Lear -1 July 2, 1946 FOREIGN PATENTS Number Country Date Great Britain Feb. 1, 1930 

